1. Field of the Invention
The invention disclosed herein relates to apparatus and systems used to purify and separate liquids and, more particularly, to apparatus and systems used to purify and separate human waste material taken from septic tanks or portable restrooms.
2. Description of the Related Art
Small-scale apparatus and systems used to treat human waste material from household septic tanks or portable restrooms are very desirable. Such apparatus and systems would enable septic tank service companies and portable restroom rental companies to efficiently process relatively small quantities of human waste material.
Septic tank service companies and portable restroom rental companies collect several hundred gallons of human waste material daily from septic tanks and portable restroom units, respectively. Typically, the waste material is temporarily collected and stored in holding tanks and then delivered to a local municipal sewer treatment facility.
Unfortunately, many municipal sewer treatment facilities in operation today will not accept such relatively large volumes of effluent waste material. Because the effluent waste material has relative high "BOD" (biochemical oxygen demand) value, the sudden introduction of large volumes of this material can disrupt the facility's sewer treatment process. Septic tank service companies and portable restroom rental companies, therefore, must find and then transport their waste material considerable distances to facilities which will accept it.
One solution to this problem is for such companies to partially treat the waste material to reduce its "BOD" value making it more accepted to the local municipal sewer treatment facility.
Another solution would be for the septic tank service companies and portable restroom rental companies to recycle a portion of the waste material so that the volume of waste material delivered to the municipal sewer treatment facility is reduced. If such companies could pretreat and then separate the waste material into waste water and sludge, the waste water could then be deposited back into the septic tank or into a nearby sewer line. For portable restroom rental companies, a portion of the waste water could also be used in clean up or reused in the portable restroom unit. For each company, the sludge could be processed "on-site" into top soil or transported to a compost treatment facility.
Today, chemical oxidation is a known method for treating waste material. In chemical oxidation, an oxidizing agent, such as chlorine gas, is dissolved in the waste material which disinfects and chemically oxidizes it. Saylor, U.S. Pat. No. 4,769,154, discloses a waste material treatment method designed for small communities or factories which uses chemical oxidization. In Saylor, a batch (approximately 85-86,000 gallons) of waste material is pumped into a receiving tank. The pH of the batch of waste material is then adjusted to approximately 7.0 using sodium hydroxide which reportedly reduces noxious odors and increases oxidation of the waste water material. After the pH has been adjusted, the batch of waste material is then transferred to a reactor chamber where pressurized chlorine gas is dissolved therein to oxidize the organic solid material. After the waste material is sufficiently oxidized, it is then transferred to a separation receptacle where the solids are allowed to float to the surface to form sludge. A polymer flocculating agent may be added to the waste material to facilitate the flocculation. The waste water, which is located below the sludge, is then rapidly drained from the separation receptacle leaving the sludge behind.
In spite of the improvements made by the treatment method disclosed in Saylor, it has several drawbacks which prevent it from being used on a smaller scale by septic tank service companies or portable restrooms rental companies. First, as noted above, the treatment method uses sodium hydroxide to raise the pH of the batch of waste material. Not only is sodium hydroxide dangerous to use, but also has been shown to be unnecessary for smaller volumes of waste material, (less than 2,000 gallons). Another drawback with using sodium hydroxide is that it may raise the pH of the waste water to unacceptable levels which make it undesirable for deposit at a municipal sewer treatment facility.
A second drawback with the treatment method disclosed in Saylor is that it uses pressurized chlorine gas to oxidize the organic particles in the waste material. Because chlorine gas is dangerous and requires special equipment and handling procedures, it is not well suited for use by septic tank service or portable restroom rental company personnel. In addition, many jurisdictions have regulations which strictly regulate the shipment, storage, and use of chlorine gas.
A third drawback with the treatment method disclosed in Saylor, is that it requires several large components such as a holding tank, a reactor tank, a separation receptacle, and various pumps, valves, and pipes. Not only are these components expensive to manufacture and operate, but also decrease the portability of tile system. Although Saylor discloses a portable embodiment of the invention, actual transporting these components on a trailer or truck bed is not practical.
A small batch waste material treatment apparatus and system which may be used by septic tank service companies or portable restroom rental companies, which do not have the above mentioned drawbacks would be very desirable.